Port of Spain (Trinidadian English: Port ah Spain [ˈpʊo̯t a ˈspɪe̯n] ) is the capital and chief port of Trinidad and Tobago. With a municipal population of 49,867 (2017), an urban population of 81,142 and a transient daily population of 250,000, it is Trinidad and Tobago's third largest municipality, after Chaguanas and San Fernando.

Port of Spain is located on the Gulf of Paria, on the northwest coast of the island of Trinidad and is part of a larger conurbation stretching from Chaguaramas in the west to Arima in the east with an estimated population of 600,000.

The city serves primarily as a retail and administrative centre and it has been the capital of the island since 1757. It is also an important financial services centre for the Caribbean and is home to two of the largest banks in the region. The Piarco International Airport is the main airport on the island, connecting the capital to various major global destinations.

Port of Spain was also the de facto capital of the short-lived West Indies Federation, which united the Caribbean.

The city is also home to the largest container port on the island and is one of several shipping hubs of the Caribbean, exporting both agricultural products and manufactured goods. Bauxite from Guyana is trans-shipped via facilities at Chaguaramas, about 8 kilometres (5 mi) west of the city. The pre-lenten Carnival is the city's main annual cultural festival and tourist attraction.

Today, Port of Spain is a leading city in the Caribbean region. Trinidad and Tobago hosted the Fifth Summit of the Americas in 2009, whose guests included US president Barack Obama and US secretary of state Hillary Clinton.

Port of Spain is also home to the biggest and most successful stock exchange in the Caribbean, the Trinidad and Tobago Stock Exchange (TTSE). The Nicholas Tower, as well as other skyscrapers, are well known throughout the region. These buildings dominate the city's skyline. Some of the tallest skyscrapers in the Caribbean are located in Port of Spain.